1. Field of the Invention
The invention relates to a drive unit for hydraulic consumers for individual structural component parts of a machine, in particular, a plastics injection molding machine, for producing shaped articles out of casting or molding materials, with a pump driven by a motor. The pump and/or the motor are connected to the machine by a carrying part.
2. Discussion of the Prior Art
To an increasing extent, noise is considered to be a nuisance also in working environments. Therefore, it is required that measures be taken to soundproof, as much as possible, drive units for hydraulic consumers that have a pump and a motor.
German reference DE 298 18 533 U1 discloses a drive unit for a hydraulically operated plastics processing machine in which essentially only the pump is surrounded by means of sound encapsulation. For this drive unit, the electric motor and the pump are attached to a motor carrier and the system including the motor pump and motor carrier is mounted in a sound-absorbing manner.
It has been shown that using a soundproofing hood of the above type is not sufficient for effectively reducing sound emission.
A constructional unit with an electric generator and a pump unit is known from German reference DE 197 50 379 A1. Here, the housing of the pump is formed by the walls of the generator housing which form the recess and by a pump cover which closes the recess in the generator housing in a liquid-tight manner and which has a suction connection opening into the recess of the generator housing. At least one directional valve is integrated at least partially in the pump cover and/or one directional valve is mounted on top of the pump cover.
The hydraulic oil taken in by the pump and flowing through the inside of the recesses is used as the coolant for the generator. Overheating of the generator is reliably prevented in this way.
This known constructional unit is driven by an internal combustion engine and is essentially used for operating structural component parts in a motor vehicle.
It is the object of the present invention to reduce in a particularly efficient manner the sound emissions of a drive unit for hydraulic consumers for individual structural component parts, in particular for a plastics injection molding machine, and, at the same time, to guarantee that the heat generated by the operation of the separate units is carried off in a simple manner.
Pursuant to this object, and others which will become apparent hereafter, one aspect of the present invention resides in a drive unit in which a carrying part that holds the motor and the pump is shaped like a pipe and both ends of the pipe are closed by a bottom and/or a cover. The pump projects into the free space of the pipe-shaped or possibly pot-shaped carrying part and does this in such a manner that it is fastened to the carrying part on the side that faces away from the motor. The area of the carrying part provided for the fastening of the pump is constructed as a connection block. In this way, pipe lines that normally would emit heat and sound are absent from the free space inside the carrying part.
The connection block is connected to a control block. In an advantageous design, the connection block and control block are integrated into the cover or the bottom of the carrying part.
The motor is attached to the side opposite to the pump attachment. The pump and the motor are connected by a rotating control coupling. In an advantageous arrangement, this coupling is designed as a splined profile. For the coupling comprising a male and a female part with a splined profile, the motor shaft is preferably constructed as a hollow shaft.
Accordingly, the pipe-shaped carrying part can be realized in such a way that only the pump is located in a soundproof chamber, or the pump as well as the motor are provided in a chamber, or both the pump and the motor each have their own chamber. If the pump and the motor are separated from one another, an opening is provided in the bottom or the cover of the carrying part. The hollow shaft of the motor enclosing the shaft of the pump is preferably guided through this opening.
The free space in the respective chamber can be filled with a fluid. This fluid can either be permanently enclosed in the chamber or can also be connected via pipe lines to a media cooling and transporting device.
When only one chamber is provided in the pipe-shaped carrying part and the pump and the motor are arranged separately from one another, a seal is provided in the opening of the cover or the bottom.
The carrying part is connected to the machine by rubber-bonded-to-metal members so as to be decoupled with respect to sound. For this purpose, the carrying part can be upright on the machine or can also be suspended from it.
In an advantageous embodiment, shaped elements, for example, fins, are provided for increasing heat dissipation and in order to increase the surface of the carrying housing. When the carrying part is a cast part, the design of the casing can be optimized with regard to the external shape of the pump or the motor as well as with regard to maximizing heat dissipation and minimizing sound emission.
Further, it is especially advantageous that the high-energy low-frequency noise (low notes) are also absorbed effectively when using a cast part due to the existing mass in this case.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.